1. Mathematical models for sequential machines;Seshu;IRE Nat. Conv. Rec.,1959
2. Gedanken experiments on sequential machines;Moore,1956
3. Logical Design of Digital Computers;Phister,1958
4. The Design of Switching Circuits;Keister,1951
5. Feedback in asynchronous sequential circuits;Friedman;IEEE Trans. Electron. Comput.,1966